To find the greatest common factor of two numbers, you first have to list each number's factors quickly — and that runs on multiplication facts and knowing what divides evenly. Get these warm and GCF feels easy.
These are words you'll need to already know to follow this lesson — not the new words the lesson teaches. Review each one, its meaning, and the example so the new lesson makes sense from the start.
Level 1 To add the same number many times to find a total.
Example: 6 × 7 means add 6 seven times to get 42.
Level 1 Two numbers you multiply together to make another number.
Example: 3 and 4 are a factor pair of 12 because 3 × 4 = 12.
Level 1 To split a number into equal groups with nothing left over.
Example: 4 divides 12 evenly because 12 ÷ 4 = 3.
Level 1 To write numbers out in order, one after another.
Example: I can list the parts of 8: 1, 2, 4, 8.
These check the skills you'll need for this lesson — not the new lesson itself. Answer all 3, then press Show my path. No grade — it just suggests where to start.
1. What is 6 × 7?
2. Which number is a factor of 12 (divides it evenly)?
3. Is 15 divisible by 3 (no remainder)?
Vocabulary previewed and basics checked. Time to start the lesson.
Start Lesson 1-2 →